Creating a particle simulation

Mocha for After Effects

In most cases, you’ll get better and more accurate tracking results using mocha from Imagineer Systems to track points in video. The mocha for After Effects tool is installed in the mocha folder in the After Effects CS5 folder on your hard drive.

One advantage of mocha for After Effects is that you don’t have to accurately place tracking points to obtain a perfect track. Rather than using tracking points, mocha for After Effects uses a planar tracker, which attempts to track an object’s translation, rotation, and scaling data based on the movement of a user-defined plane.

Planes provide more detail to the computer than is possible with single-point and multipoint tracking tools.

When you work with mocha for After Effects, you need to identify planes in a clip that coincide with movement you want to track. Planes don’t have to be tabletops or walls. For example, if someone is waving goodbye, you can use their upper and lower limbs as two planes. After you track the planes, you can export the tracking data for use in After Effects.

mocha for After Effects uses two different spline technologies for tracking: X splines and Bezier splines. X splines may work better for tracking, especially with perspective motion, but Bezier splines work well, too, and are the industry standard.

To learn more about mocha for After Effects, choose Help > Manual in mocha.

We’ve saved some tracking data for the computer monitor in mocha for After Effects, so that you can apply it in After Effects if you’d like. To apply the data, follow these steps:

1 Create a new project in After Effects, and import the majorspoilers.mov and mocha_tracking.mov files from the Lesson13/Assets folder. Create a new composition from the mocha_tracking.mov file, and then drag the majorspoilers.mov file to the top of the layer stack in the Timeline panel.

2 Open the mocha_data.txt file (in the Lesson 13/Optional_Mocha_Tutorial folder) in a text editor such as WordPad or TextEdit. (Don’t use Notepad on Windows. It doesn’t retain the mocha formatting, so After Effects doesn’t recognize its content on the clipboard.) Choose Edit > Select All, and then Edit > Copy to copy all the data.

3 Select the majorspoilers.mov layer in the Timeline panel, and choose Edit > Paste. All the data is applied to the layer.

4 Watch a RAM preview to see the results.

After Effects includes several effects that do an excellent job of creating particle simulations. Two of them—CC Particle Systems II and CC Particle World—are based on the same engine. The major difference between the two is that Particle World enables you to move the particles in 3D space, rather than a 2D layer.

In this exercise, you’ll learn how to use the CC Particle Systems II effect to create a supernova that could be used as the opening of a science program or as a motion background. If you haven’t already watched the sample movie for this exercise, do so now before continuing.

Дата добавления: 2014-11-20